Time-Domain Modeling of Transmission Line Crossing Using Electromagnetic Scattering Theory

Classical multiconductor transmission line (MTL) theory, which is employed in electromagnetic transient ( EMT) simulators, is built on the assumptions that the wire structure is infinitely long and has a uniform cross-section. Therefore, nonuniformities which occur in physical power systems, such as transmission line crossings, are not represented in classical MTL models. A new transmission line model has been developed to calculate space varying per unit length (PUL) parameter matrices near a conductor crossing using electromagnetic scattering theory. The proposed scattered field transmission line (SFTL) model has been implemented for lossless, frequency independent conductors, that cross each other at a variable crossing angle. A single dimensional finite difference time domain (1D-FDTD) algorithm has been used to obtain the time-domain solution at each simulation time-step. Obtained results have been compared with those from a 3D full-wave electromagnetic solver.